The primary objective of this study is to determine the effect of SC-58635 on renal function in patients with stable chronic renal insufficiency by comparing the changes in glomerular filtration rate (GFR) from pre- to post-dose measurements on Days 1 and 7 separately; and comparing the changes in urinary prostaglandins (PGs) from Baseline to post-dose Day 2 and Day 6, between SC-58635 and the naproxen treatment groups.